Roller hearth kiln



Y Jan. 13, 1970 J.VM. ALEXANDER ROLLER HEARTH KILN 2 Sheets-Sheet lFiled Feb. 9,

INVENTOR. -JOHN M. ALEXANDER ATTORNEY.

Jan. 13, 1970 J. M. ALEXANDER 3,489,397

ROLLER HEARTH KILN Filed Feb. 9, 1968 2 Sheets-Sheet 2 FlG. 2

v -l. 1 l 9 J @lzeM-@ l @.wzem@ 9 gef@ INVENTOR. JOHN M. ALEXANDER ATTORN EY.

United States Patent O 3,489,397 ROLLER HEARTH KILN llohn M. Alexander,Doylestown, Pa., assignor to Salas Corporation of America, a corporationof Pennsylvania Filed Feb. 9, 1968, Ser. No. 704,290 Int. Cl. F27b 9/24U.S. Cl. 263-6 9 Claims ABSTRACT OF THE DISCLOSURE A kiln for ringceramic ware having a roller hearth comprising a plurality of rollersextending from opposite sides through the walls of the kiln into thechamber. The inner ends of the rods are supported by bearing means inthe chamber while their outer ends are frictionally driven frommechanism outside the kiln chamber.

The present invention relates to kilns for firing ceramic articles suchas tiles, and more particularly to such a kiln using a roller hearth tomove the work.

In conveying small pieces of ceramic ware, such as tiles, through a kilnit is customary to use rollers made of a refractory material. Because ofthe characteristics of this material, it has not been possible to userollers of any great length. Consequently, the firing chamber of thekiln is relatively narrow, with a resultant small production capacityfor a kiln of a given length.

It is an object of the present invention to provide a roller hearth kilnwith a novel means of supporting and driving the conveyor rollers sothat the width of a kiln chamber can be materially increased.

It is a further object of the invention to provide a frictional drivefor the rollers of a roller hearth which may readily be disconnected topermit changing of the rollers, when necessary, without disturbing thenormal operation of the kiln.

These and other objects can be obtained by providing axially alignedceramic rollers extending across a kiln chamber. The inner,substantially abutting ends of the rollers are supported in a verticallyadjustable bearing member. The outer ends extend through the walls ofthe kiln and are received in sleeves that are positively driven, withthe sleeves being frictionally connected to the rolls.

The various features of novelty which characterize my invention arepointed out with particularity in the claims annexed to and forming apart of this specilication. For a better understanding of the invention,however, its advantages and specic objects attained with its use,reference should be had to the accompanying drawings and descriptivematter in which I have illustrated and described a preferred embodimentof the invention.

In the drawings:

FIG. 1 is a section across the kiln taken on line 1-1 of FIG. 2.

FIG. 2 is a view taken partially on line 2 2 of FIG. 1 and partiallyfrom outside the kiln.

FIG. 3 is a view showing the supports for the inner ends of the conveyorrods.

FIG. 4 is an enlarged view of the support and drive for the outer endsof the conveyor rolls; and

FIG. 5 is a view looking toward the end of FIG. 4 from the right.

The kiln includes a refractory structure built in accordance withordinary kiln practice and including a oor 1, side walls 2 and 3, and aroof 4 to form an elongated kiln chamber. These parts are mounted on andreinforced by a suitable supporting structure 5. The chamber is dividedinto upper and lower sections by means of a conveyor mechanism 6 formoving work to be fired through the kiln.

The conveyor includes a plurality of rods 7 that are Fice inserted'fromopposite sides, through openings provided in the side walls, toward thecenter of the chamber. The inner ends of these rods are supported bybearing blocks 8 each of which is provided with U-shaped slots orsockets 9 into which the ends of the rods are moved axially. It will beseen from FIG. 3 that the slots or sockets 9 are not as deep as thediameter of the rods 7 but that they do include slightly more than of acircle. Bearing blocks 8 rest on a beam 11 which extends lengthwise ofthe kiln chamber through the center thereof. It will be noticed that thebeam is slightly cupped on its upper surface to receive the bearingblocks and hold them in proper alignment. Beam 11 is supported at aplurality of points along its length by means of piers 12 which extendupwardly through suitable openings provided in the oor of the kiln. Thespace between the floor and the piers is normally lled with berousinsulating material in order to prevent leakage of air into the kiln.The lower ends of the piers extend between a pair of channels 13 whichare bridged by a plate 14. An adjusting bolt 15 is threaded into theplate under each pier to adjust the position of piers 12 so that beam 11will be held accurately at the proper height even though the parts mayhave some relative movement due to expansion.

The outer ends of rods 7, which extend through the walls of the chamber,pass rst through a block of close fitting insulating material 16 whichmay be librous and which serves to prevent inflow of air through theholes around the rods. Each of these rods is received in a sleeve 17that is journaled for rotation in a bearing 18 suitably mounted on theframework of the structure. Each sleeve has a sprocket 16 encircling itwith the sprockets being fastened to the sleeves by means of set screws21 that are threaded into the holes of the sprocket hub. There is africtional drive between each rod 7 and its sleeve 17 which comprises asubstantially U-shaped spring 22 that is mounted on a pin 23 attached tothe hub of sprocket 19. The legs of these springs are received in slots24 formed on opposite sides of sleeve 17 so that the legs of the springare in frictional engagement with the surface of the rods. If it isdesired, small flats can be formed on the rods where they are engaged bythe springs in order to give a more positive drive. It is intended thatthe rods be driven at the same speed as the sleeves but that there canbe slippage between the rods and the sleeves, if necessary. Each of thesprockets is driven by a chain 25 at the speed necessary to move thework through the kiln while it is being lired. Burners 26 are shown inthe side walls above and below the conveyor mechanism so that heat willbe applied evenly to the top and bottom of ware 27, disclosed herein asbeing tiles.

The rods 7 are preferably made of a ceramic material Which is capable ofwithstanding the heat of the kiln. In order to reduce their weight, theyare usually, and are shown herein, as being in the form of ceramictubes. Rods extending inwardly from opposite sides of the kiln areaxially aligned with each other and the abutting ends of two rods arereceived in each 0f the sockets 9. These sockets are formed in bearingblocks 8 which are preferably made 'of a hard ceramic material with thesurface of the slots being polished to reduce friction. The bearingblocks can be made as a continuous member, but are preferably made inseg-ments, as shown, to prevent misalignment due to expansion. Fortiring relatively small tiles, the rods will be about 1" in diameter andwill be placed on 2" centers. Since the rods are so close together thesprockets driving the sleeves will preferably be offset axially withrespect to each other as shown on the right hand portion of FIG. 2. Thismeans that there will be two parallel chains 25 on each side of the kilnin order to drive all of the rods. While the rods on each side aredriven independently, the drive for the four chains can come from asingle source so that all of the rods Will rotate at the same speed. Therods will normally rotate at from 31/2 to 4 revolutions per minute.

In the past it has been suggested that ceramic rods of the typedisclosed herein should be used for forwarding ware through a kiln; butbecause of the brittle nature of these rods and their relatively smalldiameter, it has been necessary to make the kilns relatively narrow sothat the rods can be supported on outboard bearings at both ends. Withthe present invention the manner of supporting and driving the rodspermits the kiln to be considerably wider than is customary and therebysubstantially increases the capacity of the kiln of a given length. Ineifect, separate groups of ware are being forwarded by the separate setsof rods. It is noted that if there is a jam-up in the kiln, as happensfrom time to time in spite of all precautions, the drive can continuebut due to the springs 22 those rods affected can stay still until thejam has been cleared away. If perchance one of the rods is broken it canreadily be removed and a new one inserted without stopping or coolingthe kiln. It is only necessary to move the lower handlelike ends of aspring 22 together to relieve its frictional engagement on the end ofthe rod. The rod can then be removed axially and replaced in a matter ofminutes. Broken tiles and portions of broken rods, if any should break,will fall to the bottom of the kiln and may be removed through suitableopenings provided in the side walls.

While in accordance with the provisions of the Statutes I haveillustrated and described the best form of embodiment of my inventionnow known to me, it will be apparent to those skilled in the art thatchanges -may be made in the form of the apparatus disclosed withoutdeparting from the spirit and scope of the invention, and that in somecases certain features of my invention may be used to advantage Withouta corresponding use of other features.

What is claimed is:

1. Conveyor mechanism for moving Work to be iired through an elongatedkiln having an elongated chamber with side walls including a pluralityof rods extending in parallel relation through openings in a side wallinto said chamber, means in said chamber to support one end of each ofsaid rods for rotation, means outside said side wall to support theother end of and to rotate said rods, said last means including atubular sleeve receiving each rod, a bearing supporting each sleeve forrotation, means to rotate said sleeves in unison, and a friction drivebetween each sleeve and the rods received therein.

2. The combination of claim 1 in which said friction drive includesspring means attached to each said sleeve and normally biased toward theaxis of said sleeve through a slot formed in said sleeve substantiallyperpendicular to said axis, said spring means frictionally engaging thesurface of a rod extending through said sleeve.

3. The combination of claim 1 in which said means to hold said one endof said rods includes a member extending lengthwise of said chamber,said member having a plurality of sockets formed therein into which saidends of said rods extend, and means to release said friction driveswhereby said rods may be moved axially through said sleeves, across saidchamber and into said socket.

4. The combination of claim 3 including means to adjust said membervertically thereby to align said sockets with said openings.

5. In a continuous kiln, structure forming an elongated chamber havingside walls, a iloor and a roof, means to move separate groups of ware tobe iired through said chamber independently comprising a plurality ofrods for supporting one group of Ware extending through one of said sidewalls toward the center of said chamber, a plurality of rods forsupporting another group of ware extending through the other side walltoward the center of said chamber, the rods extending through one sidewall being axially aligned with the rods extending through the otherwall, means extending lengthwise through the center of said chamber tosupport the inner ends of each of said pluraltiy of rods for rotation,and separate means beyond said side walls to rotate each of saidplurality of rods.

6. The combintion of claim 5 in which said means extending lengthwisethrough said chamber includes a beam, and means on said beam havingU-shaped slots formed therein, each of said slots receiving therein theends of a pair of axially aligned rods.

7. The combination of claim 6 in which said beam is lsupported by aplurality of piers extending upwardly UNITED STATES PATENTS 1,927,6349/1933 Fahrenwald. 2,175,834 10/1939 Fatkin.

3,338,569 8/1967 Cuvelier.

JOHN J. CAMBY, Primary Examiner U.S. Cl. X.R. 29-115

